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Pomeroy E. Review: The different adaptive trajectories in Neanderthals and Homo sapiens and their implications for contemporary human physiological variation. Comp Biochem Physiol A Mol Integr Physiol 2023; 280:111420. [PMID: 37001690 DOI: 10.1016/j.cbpa.2023.111420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023]
Abstract
Neanderthals are our one of our closest evolutionary cousins, but while they evolved in Eurasia, we (anatomically modern humans, AMH) originated in Africa. This contrasting evolutionary history has led to morphological and genetic distinctions between our species. Neanderthals are characterised by a relatively stocky build, high body mass, proportionally wide bodies and shorter limbs, a bell-shaped ribcage with a wide pelvis, and a long, low cranial vault compared with AMH. Classic readings of Neanderthal morphology link many of these traits to cold climate adaptations, however these interpretations have been questioned and alternative hypotheses including behavioural factors, dietary adaptations, locomotor specialisations, evolutionary history and neutral evolutionary processes have been invoked. Compared with AMH, Neanderthals may have been adapted for strength and power rather than endurance and may have consumed a diet high in animal products. However, reviewing these hypotheses highlights a number of limitations in our understanding of contemporary human physiology and metabolism, including the relationship between climate and morphology in AMH and Neanderthals, physiological limits on protein consumption, and the relationship between gut morphology and diet. As various relevant factors are clearly linked (e.g. diet, behaviour, metabolism, morphology, activity), ultimately a more integrated approach may be needed to fully understand Neanderthal biology. Variation among contemporary AMHs may offer, with caveats, a useful model for understanding the evolution of both Neanderthal and modern human characteristics, which in turn may further deepen our understanding of variability within and between contemporary humans. Neanderthals; Anatomically modern humans; morphology; climate adaptation; power adaptations; metabolism; diet; physiology; endurance running.
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Mörseburg A, Pagani L, Malyarchuk B, Derenko M, Kivisild T. Response to Wyckelsma et al.: Loss of α-actinin-3 during human evolution provides superior cold resilience and muscle heat generation. Am J Hum Genet 2022; 109:967-972. [PMID: 35523147 PMCID: PMC9118108 DOI: 10.1016/j.ajhg.2022.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 03/18/2022] [Indexed: 11/19/2022] Open
Abstract
The common loss-of-function mutation R577X in the structural muscle protein ACTN3 emerged as a potential target of positive selection from early studies and has been the focus of insightful physiological work suggesting a significant impact on muscle metabolism. Adaptation to cold climates has been proposed as a key adaptive mechanism explaining its global allele frequency patterns. Here, we re-examine this hypothesis analyzing modern (n = 3,626) and ancient (n = 1,651) genomic data by using allele-frequency as well as haplotype homozygosity-based methods. The presented results are more consistent with genetic drift rather than selection in cold climates as the main driver of the ACTN3 R577X frequency distribution in human populations across the world. This Matters Arising paper is in response to Wyckelsma et al. (2021),1 published in The American Journal of Human Genetics. See also the response by Wyckelsma et al. (2022),2 published in this issue.
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Affiliation(s)
- Alexander Mörseburg
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK.
| | - Luca Pagani
- Estonian Biocentre, Institute of Genomics, University of Tartu, Riia 23B, Tartu 51010, Estonia; Department of Biology, University of Padova, 35131 Padova, Italy
| | - Boris Malyarchuk
- Genetics Laboratory, Institute of Biological Problems of the North, Russian Academy of Sciences, Portovaya str. 18, Magadan 685000, Russia
| | - Miroslava Derenko
- Genetics Laboratory, Institute of Biological Problems of the North, Russian Academy of Sciences, Portovaya str. 18, Magadan 685000, Russia
| | - Toomas Kivisild
- Estonian Biocentre, Institute of Genomics, University of Tartu, Riia 23B, Tartu 51010, Estonia; Department of Human Genetics, KU Leuven, Leuven, Herestraat 3000, Belgium.
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Barrón-Cabrera E, Torres-Castillo N, González-Becerra K, Zepeda-Carrillo EA, Torres-Valadez R, Hernández-Cañaveral I, Martínez-López E. The ACTN3 R577X polymorphism is associated with metabolic alterations in a sex-dependent manner in subjects from western Mexico. J Hum Nutr Diet 2021; 35:713-721. [PMID: 34750902 DOI: 10.1111/jhn.12948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/13/2021] [Indexed: 01/10/2023]
Abstract
BACKGROUND The ACTN3 gene is primarily expressed in fast skeletal muscle fibres. A common nonsense polymorphism in this gene is ACTN3 R577X (rs1815739), which causes an absolute deficiency of α-actinin-3 protein and alterations in muscle metabolism. Considering metabolic alterations are influenced by nutrition and genetic factors, as well as lifestyle factors, we hypothesise a possible association of the ACTN3 R577X polymorphism with metabolic alterations. METHODS In this cross-sectional study, 397 adults met the inclusion criteria. Body composition was measured by electrical bioimpedance. Dietary data were analysed using Nutritionist Pro™ software. Biochemical variables were determined by dry chemistry. Genomic DNA was extracted from peripheral leukocytes and genotyping of the ACTN3 R577X polymorphism was determined by allelic discrimination using TaqMan probes. The statistical analyses were performed using SPSS statistical software. p < 0.05 was considered statistically significant. RESULTS The ACTN3 577XX genotype was associated with high glucose, triglyceride and very low density lipoprotein-cholesterol levels and a higher frequency of hypertriglyceridaemia and insulin resistance in women. In males, the genetic variant showed a trend towards significance for insulin resistance. CONCLUSIONS The ACTN3 R577X polymorphism was associated with metabolic alterations in women and a tendency was observed in men variant carriers. Thus, this common genetic variant could be implicated in the development of chronic metabolic diseases.
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Affiliation(s)
- Elisa Barrón-Cabrera
- Departamento de Biología Molecular y Genómica, Centro Universitario de Ciencias de la Salud, Instituto de Nutrigenética y Nutrigenómica Traslacional, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - Nathaly Torres-Castillo
- Departamento de Biología Molecular y Genómica, Centro Universitario de Ciencias de la Salud, Instituto de Nutrigenética y Nutrigenómica Traslacional, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - Karina González-Becerra
- Departamento de Biología Molecular y Genómica, Centro Universitario de Ciencias de la Salud, Instituto de Nutrigenética y Nutrigenómica Traslacional, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - Eloy A Zepeda-Carrillo
- Centro Nayarita de Innovación y Transferencia de Tecnología, Universidad Autónoma de Nayarit, Tepic, Nayarit, México.,Hospital Civil Dr Antonio González Guevara, Servicios de Salud de Nayarit, Tepic, Nayarit, Mexico
| | - Rafael Torres-Valadez
- Centro Nayarita de Innovación y Transferencia de Tecnología, Universidad Autónoma de Nayarit, Tepic, Nayarit, México.,Unidad Académica de Salud Integral, Universidad Autónoma de Nayarit, Tepic, Nayarit, Mexico
| | - Iván Hernández-Cañaveral
- Departamento de Microbiología y Patología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, México
| | - Erika Martínez-López
- Departamento de Biología Molecular y Genómica, Centro Universitario de Ciencias de la Salud, Instituto de Nutrigenética y Nutrigenómica Traslacional, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
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Anemia in Sports: A Narrative Review. Life (Basel) 2021; 11:life11090987. [PMID: 34575136 PMCID: PMC8472039 DOI: 10.3390/life11090987] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/06/2021] [Accepted: 09/16/2021] [Indexed: 12/12/2022] Open
Abstract
Recent years have brought about new understandings regarding the pathogenesis of anemia in sports. From hemodilution and redistribution considered to contribute to the so-called “sports anemia” to iron deficiency caused by increased demands, dietary restrictions, decreased absorption, increased losses, hemolysis, and sequestration, to genetic determinants of different types of anemia (some related to sport), the anemia in athletes deserves a careful and multifactorial approach. Dietary factors that reduce iron absorption (e.g., phytate, polyphenols) and that augment iron’s bioavailability (e.g., ascorbic acid) should be considered. Celiac disease, more prevalent in female athletes, may underlie an unexplained iron deficiency anemia. Iron loss during exercise occurs in several ways: sweating, hematuria, gastrointestinal bleeding, inflammation, and intravascular and extravascular hemolysis. From a practical point of view, assessing iron status, especially in the athletes at risk for iron deficiency (females, adolescents, in sports with dietary restrictions, etc.), may improve the iron balance and possibly the performance. Hemoglobin and serum ferritin are measures that are easily employable for the evaluation of patients’ iron status. Cutoff values should probably be further assessed with respect to the sex, age, and type of sport. A healthy gut microbiome influences the iron status. Athletes at risk of iron deficiency should perform non-weight-bearing, low-intensity sports to avoid inducing hemolysis.
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ACTN3 Genotypes and Their Relationship with Muscle Mass and Function of Kosovan Adults. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18179135. [PMID: 34501725 PMCID: PMC8431689 DOI: 10.3390/ijerph18179135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/21/2021] [Accepted: 08/27/2021] [Indexed: 12/21/2022]
Abstract
Maintaining muscle mass and function is important throughout the lifestyle. While environmental factors such as physical activity and healthy nutrition are well investigated, the contribution of genetic factors is still controversial. Therefore, we aimed to investigate the impact of a common ACTN3 polymorphism (rs1815739) on body composition, handgrip strength, knee extensor peak torque, and physical performance (gait speed, 30-s arm curl, 30-s chair stand) in Kosovan adults. In total, 308 participants (160 females and 148 males, age range from 40 to 91 years) took part in this cross-sectional study. Genomic DNA was extracted from saliva and assessed for ACTN3 genotype distribution (41.5% of RR, 53.9% of RX and 4.6% of XX). Genotype allocation did not account for differences in any of the variables. Interestingly, female XX carriers were taller (p = 0.025) and had a higher isokinetic knee extension peak torque (p = 0.024) than the RX+RR group. In males, XX carriers were also taller (p = 0.049) and had a lower BMI (p = 0.026), but did not differ in any of the strength and performance parameters. These results indicate that the ACTN3 R577X polymorphism might exert a sex-specific impact on knee extensor peak torque and BMI.
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Seto JT, Roeszler KN, Meehan LR, Wood HD, Tiong C, Bek L, Lee SF, Shah M, Quinlan KGR, Gregorevic P, Houweling PJ, North KN. ACTN3 genotype influences skeletal muscle mass regulation and response to dexamethasone. SCIENCE ADVANCES 2021; 7:eabg0088. [PMID: 34215586 PMCID: PMC11060041 DOI: 10.1126/sciadv.abg0088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 05/19/2021] [Indexed: 06/13/2023]
Abstract
Homozygosity for the common ACTN3 null polymorphism (ACTN3 577X) results in α-actinin-3 deficiency in ~20% of humans worldwide and is linked to reduced sprint and power performance in both elite athletes and the general population. α-Actinin-3 deficiency is also associated with reduced muscle mass, increased risk of sarcopenia, and altered muscle wasting response induced by denervation and immobilization. Here, we show that α-actinin-3 plays a key role in the regulation of protein synthesis and breakdown signaling in skeletal muscle and influences muscle mass from early postnatal development. We also show that α-actinin-3 deficiency reduces the atrophic and anti-inflammatory response to the glucocorticoid dexamethasone in muscle and protects against dexamethasone-induced muscle wasting in female but not male mice. The effects of α-actinin-3 deficiency on muscle mass regulation and response to muscle wasting provide an additional mechanistic explanation for the positive selection of the ACTN3 577X allele in recent human history.
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Affiliation(s)
- Jane T Seto
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Kelly N Roeszler
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Lyra R Meehan
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Harrison D Wood
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Chrystal Tiong
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Lucinda Bek
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Siaw F Lee
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Manan Shah
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Kate G R Quinlan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Paul Gregorevic
- Centre for Muscle Research, Department of Physiology, University of Melbourne, Melbourne, VIC, Australia
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Peter J Houweling
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Kathryn N North
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia.
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
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Loss of α-actinin-3 during human evolution provides superior cold resilience and muscle heat generation. Am J Hum Genet 2021; 108:446-457. [PMID: 33600773 PMCID: PMC8008486 DOI: 10.1016/j.ajhg.2021.01.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/19/2021] [Indexed: 12/12/2022] Open
Abstract
The protein α-actinin-3 expressed in fast-twitch skeletal muscle fiber is absent in 1.5 billion people worldwide due to homozygosity for a nonsense polymorphism in ACTN3 (R577X). The prevalence of the 577X allele increased as modern humans moved to colder climates, suggesting a link between α-actinin-3 deficiency and improved cold tolerance. Here, we show that humans lacking α-actinin-3 (XX) are superior in maintaining core body temperature during cold-water immersion due to changes in skeletal muscle thermogenesis. Muscles of XX individuals displayed a shift toward more slow-twitch isoforms of myosin heavy chain (MyHC) and sarcoplasmic reticulum (SR) proteins, accompanied by altered neuronal muscle activation resulting in increased tone rather than overt shivering. Experiments on Actn3 knockout mice showed no alterations in brown adipose tissue (BAT) properties that could explain the improved cold tolerance in XX individuals. Thus, this study provides a mechanism for the positive selection of the ACTN3 X-allele in cold climates and supports a key thermogenic role of skeletal muscle during cold exposure in humans.
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Effect of ACTN3 Genotype on Sports Performance, Exercise-Induced Muscle Damage, and Injury Epidemiology. Sports (Basel) 2020; 8:sports8070099. [PMID: 32668587 PMCID: PMC7404684 DOI: 10.3390/sports8070099] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/30/2020] [Accepted: 07/09/2020] [Indexed: 12/20/2022] Open
Abstract
Genetic factors play a significant role in athletic performance and its related phenotypes such as power, strength and aerobic capacity. In this regard, the lack of a muscle protein due to a genetic polymorphism has been found to affect sport performance in a wide variety of ways. α-actinin-3 is a protein located within the skeletal muscle with a key role in the production of sarcomeric force. A common stop-codon polymorphism (rs1815739; R577X) in the gene that codes for α-actinin-3 (ACTN3) produces individuals with the XX genotype that lack expression of a functional α-actinin-3. In contrast, individuals with the R-allele (i.e., RX vs. RR genotypes) in this polymorphism can express α-actinin-3. Interestingly, around ~18% of the world population have the XX genotype and much has been debated about why a polymorphism that produces a lack of a muscle protein has endured natural selection. Several investigations have found that α-actinin-3 deficiency due to XX homozygosity in the ACTN3 R577X polymorphism can negatively affect sports performance through several structural, metabolic, or signaling changes. In addition, new evidence suggests that α-actinin-3 deficiency may also impact sports performance through indirect factors such a higher risk for injury or lower resistance to muscle-damaging exercise. The purpose of this discussion is to provide a clear explanation of the effect of α-actinin-3 deficiency due to the ACTN3 XX genotype on sport. Key focus has been provided about the effect of α-actinin-3 deficiency on morphologic changes in skeletal muscle, on the low frequency of XX athletes in some athletic disciplines, and on injury epidemiology.
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Goleva-Fjellet S, Bjurholt AM, Kure EH, Larsen IK, Støren Ø, Sæbø M. Distribution of allele frequencies for genes associated with physical activity and/or physical capacity in a homogenous Norwegian cohort- a cross-sectional study. BMC Genet 2020; 21:8. [PMID: 31973699 PMCID: PMC6979285 DOI: 10.1186/s12863-020-0813-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 01/16/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND There are large individual differences in physical activity (PA) behavior as well as trainability of physical capacity. Heritability studies have shown that genes may have as much impact on exercise participation behavior as environmental factors. Genes that favor both trainability and participation may increase the levels of PA. The present study aimed to assess the allele frequencies in genes associated with PA and/or physical capacity, and to see if there is any association between these polymorphisms and self-reported PA levels in a cohort of middle-aged Norwegians of Scandinavian descent (n = 831; mean age mean age (± SD) 55.5 ± 3.8 years). RESULTS The genotype distributions of the ACTN3 R577X, ACE I/D and MAOA uVNTR polymorphisms were similar to other populations of European descent. When comparing the genotype distribution between the low/medium level PA group (LMPA) and high level PA groups (HPA), a significant difference in ACTN3 577X allele distribution was found. The X allele frequency was 10% lower in the HPA level group (P = 0.006). There were no differences in the genotype distribution of the ACE I/D or MAOA uVNTR polymorphism. Education and previous participation in sports or outdoor activities was positively associated with the self-reported PA levels (P ≤ 0.001). CONCLUSIONS To the best of our knowledge, this is the first study to report association between ACTN3 R577X genotype and PA level in middle-aged Scandinavians. Nevertheless, the contribution of a single polymorphism to a complex trait, like PA level, is likely small. Socioeconomic variables, as education and previous participation in sports or outdoor activities, are positively associated with the self-reported PA levels.
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Affiliation(s)
- Sannija Goleva-Fjellet
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Gullbringvegen 36, 3800, Bø i, Telemark, Norway.
| | - Anne Mari Bjurholt
- Department of Sports, Physical Education and Outdoor Studies, University of South-Eastern Norway, Gullbringvegen 36, 3800, Bø i, Telemark, Norway
| | - Elin H Kure
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Gullbringvegen 36, 3800, Bø i, Telemark, Norway.,Department of Cancer Genetics, Institute for Cancer Research, Oslo University Hospital-The Norwegian Radium Hospital, Oslo, Norway
| | | | - Øyvind Støren
- Department of Sports, Physical Education and Outdoor Studies, University of South-Eastern Norway, Gullbringvegen 36, 3800, Bø i, Telemark, Norway
| | - Mona Sæbø
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Gullbringvegen 36, 3800, Bø i, Telemark, Norway
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ACTN3 R577X Genotype and Exercise Phenotypes in Recreational Marathon Runners. Genes (Basel) 2019; 10:genes10060413. [PMID: 31146466 PMCID: PMC6627880 DOI: 10.3390/genes10060413] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 12/29/2022] Open
Abstract
Background: Homozygosity for the X-allele in the ACTN3 R577X (rs1815739) polymorphism results in the complete absence of α-actinin-3 in sarcomeres of fast-type muscle fibers. In elite athletes, the ACTN3 XX genotype has been related to inferior performance in speed and power-oriented sports; however, its influence on exercise phenotypes in recreational athletes has received less attention. We sought to determine the influence of ACTN3 genotypes on common exercise phenotypes in recreational marathon runners. Methods: A total of 136 marathoners (116 men and 20 women) were subjected to laboratory testing that included measurements of body composition, isometric muscle force, muscle flexibility, ankle dorsiflexion, and the energy cost of running. ACTN3 genotyping was performed using TaqMan probes. Results: 37 runners (27.2%) had the RR genotype, 67 (49.3%) were RX and 32 (23.5%) were XX. There was a difference in body fat percentage between RR and XX genotype groups (15.7 ± 5.8 vs. 18.8 ± 5.5%; effect size, ES, = 0.5 ± 0.4, p = 0.024), whereas the distance obtained in the sit-and-reach-test was likely lower in the RX than in the XX group (15.3 ± 7.8 vs. 18.4 ± 9.9 cm; ES = 0.4 ± 0.4, p = 0.046). Maximal dorsiflexion during the weight-bearing lunge test was different in the RR and XX groups (54.8 ± 5.8 vs. 57.7 ± 5.1 degree; ES = 0.5 ± 0.5, p = 0.044). Maximal isometric force was higher in the RR than in the XX group (16.7 ± 4.7 vs. 14.7 ± 4.0 N/kg; ES = −0.5 ± 0.3, p = 0.038). There was no difference in the energy cost of running between genotypes (~4.8 J/kg/min for all three groups, ES ~0.2 ± 0.4). Conclusions: The ACTN3 genotype might influence several exercise phenotypes in recreational marathoners. Deficiency in α-actinin-3 might be accompanied by higher body fatness, lower muscle strength and higher muscle flexibility and range of motion. Although there is not yet a scientific rationale for the use of commercial genetic tests to predict sports performance, recreational marathon runners who have performed such types of testing and have the ACTN3 XX genotype might perhaps benefit from personalized strength training to improve their performance more than their counterparts with other ACTN3 genotypes.
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Jia JL, Chen S, Sivarajah V, Stephens D, Cortez MA. Latitudinal differences on the global epidemiology of infantile spasms: systematic review and meta-analysis. Orphanet J Rare Dis 2018; 13:216. [PMID: 30486850 PMCID: PMC6262963 DOI: 10.1186/s13023-018-0952-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/14/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Infantile spasms represent the catastrophic, age-specific seizure type associated with acute and long-term neurological morbidity. However, due to rarity and heterogenous determination, there is persistent uncertainty of its pathophysiological and epidemiological characteristics. The purpose of the current study was to address a historically suspected latitudinal basis of infantile spasms incidence, and to interrogate a geographical basis of epidemiology, including the roles of latitude and other environmental factors, using meta-analytic and -regression methods. METHODS A systematic search was performed in Ovid MEDLINE and Embase for primary reports on infantile spasms incidence and prevalence epidemiology. RESULTS One thousand fifteen studies were screened to yield 54 eligible publications, from which 39 incidence figures and 18 prevalence figures were extracted. The pooled incidence was 0.249 cases/1000 live births. The pooled prevalence was 0.015 cases/1000 population. Univariate meta-regression determined a continental effect, with Europe demonstrating the highest onset compared from Asia (OR = 0.51, p = 0.004) and from North America (OR = 0.50, p = 0.004). Latitude was also positively correlated with incidence globally (OR = 1.02, p < 0.001). Sub-analyses determined a particularly elevated Scandinavian incidence compared to the rest of world (OR = 1.88, p < 0.001), and lack of latitudinal effect with Scandinavian exclusion (p = 0.10). Metrics of healthcare quality did not predict incidence. Multiple meta-regression determined that latitude was the key predictor of incidence (OR = 1.02, p = 0.001). CONCLUSIONS This is the first systematic epidemiological study of infantile spasms. Limitations included lack of Southern hemispheric representation, insufficient study selection and size to support some sub-continental analyses, and lack of accessible ethnic and healthcare quality data. Meta-analyses determined a novel, true geographical difference in incidence which is consistent with a latitudinal and/or ethnic contribution to epileptogenesis. These findings justify the establishment of a global registry of infantile spasms epidemiology to promote future systematic studies, clarify risk factors, and expand understanding of the pathophysiology.
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Affiliation(s)
- Jason L. Jia
- Department of Medicine, University of Toronto, 190 Elizabeth Street R. Fraser Elliott Wing, Toronto, M5G 2C4 Canada
| | - Shiyi Chen
- Child Health Evaluative Sciences Research Program, SickKids Research Institute, The Hospital for Sick Children, Toronto, Canada
| | - Vishalini Sivarajah
- Department of Medicine, University of Toronto, 190 Elizabeth Street R. Fraser Elliott Wing, Toronto, M5G 2C4 Canada
| | - Derek Stephens
- Child Health Evaluative Sciences Research Program, SickKids Research Institute, The Hospital for Sick Children, Toronto, Canada
| | - Miguel A. Cortez
- Department of Pediatrics, Division of Neurology, University of Toronto, Toronto, Canada
- Neurosciences & Mental Health Program, Peter Gilgan Centre for Research and Learning, SickKids Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8 Canada
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13
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Houweling PJ, Papadimitriou ID, Seto JT, Pérez LM, Coso JD, North KN, Lucia A, Eynon N. Is evolutionary loss our gain? The role of
ACTN3
p.Arg577Ter (R577X) genotype in athletic performance, ageing, and disease. Hum Mutat 2018; 39:1774-1787. [DOI: 10.1002/humu.23663] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 09/20/2018] [Accepted: 09/26/2018] [Indexed: 01/13/2023]
Affiliation(s)
- Peter J. Houweling
- Murdoch Children's Research Institute Melbourne, Victoria Australia
- Department of Paediatrics University of Melbourne The Royal Children's Hospital Melbourne, Victoria Australia
| | | | - Jane T. Seto
- Murdoch Children's Research Institute Melbourne, Victoria Australia
- Department of Paediatrics University of Melbourne The Royal Children's Hospital Melbourne, Victoria Australia
| | - Laura M. Pérez
- Universidad Europea de Madrid (Faculty of Sport Sciences) Madrid Spain
- Instituto de Investigación Hospital 12 de Octubre Madrid Spain
| | - Juan Del Coso
- Exercise Physiology Laboratory Camilo José Cela University Madrid Spain
| | - Kathryn N. North
- Murdoch Children's Research Institute Melbourne, Victoria Australia
- Department of Paediatrics University of Melbourne The Royal Children's Hospital Melbourne, Victoria Australia
| | - Alejandro Lucia
- Universidad Europea de Madrid (Faculty of Sport Sciences) Madrid Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable Madrid Spain
| | - Nir Eynon
- Institute for Health and Sport (iHeS) Victoria University Victoria Australia
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Del Coso J, Hiam D, Houweling P, Pérez LM, Eynon N, Lucía A. More than a 'speed gene': ACTN3 R577X genotype, trainability, muscle damage, and the risk for injuries. Eur J Appl Physiol 2018; 119:49-60. [PMID: 30327870 DOI: 10.1007/s00421-018-4010-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/05/2018] [Indexed: 12/11/2022]
Abstract
A common null polymorphism (rs1815739; R577X) in the gene that codes for α-actinin-3 (ACTN3) has been related to different aspects of exercise performance. Individuals who are homozygous for the X allele are unable to express the α-actinin-3 protein in the muscle as opposed to those with the RX or RR genotype. α-actinin-3 deficiency in the muscle does not result in any disease. However, the different ACTN3 genotypes can modify the functioning of skeletal muscle during exercise through structural, metabolic or signaling changes, as shown in both humans and in the mouse model. Specifically, the ACTN3 RR genotype might favor the ability to generate powerful and forceful muscle contractions. Leading to an overall advantage of the RR genotype for enhanced performance in some speed and power-oriented sports. In addition, RR genotype might also favor the ability to withstand exercise-induced muscle damage, while the beneficial influence of the XX genotype on aerobic exercise performance needs to be validated in human studies. More information is required to unveil the association of ACTN3 genotype with trainability and injury risk during acute or chronic exercise.
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Affiliation(s)
- Juan Del Coso
- Exercise Physiology Laboratory, Camilo José Cela University, Madrid, Spain.
| | - Danielle Hiam
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | | | - Laura M Pérez
- Universidad Europea de Madrid (Faculty of Sport Sciences) and Research Institute i+12, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - Nir Eynon
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia.,Murdoch Childrens Research Institute, Melbourne, Australia
| | - Alejandro Lucía
- Universidad Europea de Madrid (Faculty of Sport Sciences) and Research Institute i+12, Madrid, Spain
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16
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GARTON FLEURC, NORTH KATHRYNN. The Effect of Heterozygosity for the ACTN3 Null Allele on Human Muscle Performance. Med Sci Sports Exerc 2016; 48:509-20. [DOI: 10.1249/mss.0000000000000784] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Hogarth MW, Garton FC, Houweling PJ, Tukiainen T, Lek M, Macarthur DG, Seto JT, Quinlan KGR, Yang N, Head SI, North KN. Analysis of the ACTN3 heterozygous genotype suggests that α-actinin-3 controls sarcomeric composition and muscle function in a dose-dependent fashion. Hum Mol Genet 2016; 25:866-77. [PMID: 26681802 PMCID: PMC4754040 DOI: 10.1093/hmg/ddv613] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/14/2015] [Indexed: 11/13/2022] Open
Abstract
A common null polymorphism (R577X) in ACTN3 causes α-actinin-3 deficiency in ∼ 18% of the global population. There is no associated disease phenotype, but α-actinin-3 deficiency is detrimental to sprint and power performance in both elite athletes and the general population. However, despite considerable investigation to date, the functional consequences of heterozygosity for ACTN3 are unclear. A subset of studies have shown an intermediate phenotype in 577RX individuals, suggesting dose-dependency of α-actinin-3, while others have shown no difference between 577RR and RX genotypes. Here, we investigate the effects of α-actinin-3 expression level by comparing the muscle phenotypes of Actn3(+/-) (HET) mice to Actn3(+/+) [wild-type (WT)] and Actn3(-/-) [knockout (KO)] littermates. We show reduction in α-actinin-3 mRNA and protein in HET muscle compared with WT, which is associated with dose-dependent up-regulation of α-actinin-2, z-band alternatively spliced PDZ-motif and myotilin at the Z-line, and an incremental shift towards oxidative metabolism. While there is no difference in force generation, HET mice have an intermediate endurance capacity compared with WT and KO. The R577X polymorphism is associated with changes in ACTN3 expression consistent with an additive model in the human genotype-tissue expression cohort, but does not influence any other muscle transcripts, including ACTN2. Overall, ACTN3 influences sarcomeric composition in a dose-dependent fashion in mouse skeletal muscle, which translates directly to function. Variance in fibre type between biopsies likely masks this phenomenon in human skeletal muscle, but we suggest that an additive model is the most appropriate for use in testing ACTN3 genotype associations.
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Affiliation(s)
- Marshall W Hogarth
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, Sydney, NSW 2145, Australia, Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, NSW 2006, Australia
| | - Fleur C Garton
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, Sydney, NSW 2145, Australia, Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, NSW 2006, Australia, Murdoch Children's Research Institute, Melbourne, Vic 3052, Australia, Department of Paediatrics, University of Melbourne, Melbourne, Vic, Australia
| | - Peter J Houweling
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, Sydney, NSW 2145, Australia, Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, NSW 2006, Australia, Murdoch Children's Research Institute, Melbourne, Vic 3052, Australia, Department of Paediatrics, University of Melbourne, Melbourne, Vic, Australia
| | - Taru Tukiainen
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA, Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA and
| | - Monkol Lek
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA, Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA and
| | - Daniel G Macarthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA, Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA and
| | - Jane T Seto
- Murdoch Children's Research Institute, Melbourne, Vic 3052, Australia, Department of Paediatrics, University of Melbourne, Melbourne, Vic, Australia
| | - Kate G R Quinlan
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, Sydney, NSW 2145, Australia, Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, NSW 2006, Australia
| | - Nan Yang
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, Sydney, NSW 2145, Australia
| | - Stewart I Head
- School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Kathryn N North
- Institute for Neuroscience and Muscle Research, The Children's Hospital Westmead, Sydney, NSW 2145, Australia, Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, NSW 2006, Australia, Murdoch Children's Research Institute, Melbourne, Vic 3052, Australia, Department of Paediatrics, University of Melbourne, Melbourne, Vic, Australia,
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Evidence for ACTN3 as a Speed Gene in Isolated Human Muscle Fibers. PLoS One 2016; 11:e0150594. [PMID: 26930663 PMCID: PMC4773019 DOI: 10.1371/journal.pone.0150594] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 02/17/2016] [Indexed: 01/22/2023] Open
Abstract
Purpose To examine the effect of α-actinin-3 deficiency due to homozygosity for the ACTN3 577X-allele on contractile and morphological properties of fast muscle fibers in non-athletic young men. Methods A biopsy was taken from the vastus lateralis of 4 RR and 4 XX individuals to test for differences in morphologic and contractile properties of single muscle fibers. The cross-sectional area of the fiber and muscle fiber composition was determined using standard immunohistochemistry analyses. Skinned single muscle fibers were subjected to active tests to determine peak normalized force (P0), maximal unloading velocity (V0) and peak power. A passive stretch test was performed to calculate Young’s Modulus and hysteresis to assess fiber visco-elasticity. Results No differences were found in muscle fiber composition. The cross-sectional area of type IIa and IIx fibers was larger in RR compared to XX individuals (P<0.001). P0 was similar in both groups over all fiber types. A higher V0 was observed in type IIa fibers of RR genotypes (P<0.001) but not in type I fibers. The visco-elasticity as determined by Young’s Modulus and hysteresis was unaffected by fiber type or genotype. Conclusion The greater V0 and the larger fast fiber CSA in RR compared to XX genotypes likely contribute to enhanced whole muscle performance during high velocity contractions.
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Lee FXZ, Houweling PJ, North KN, Quinlan KGR. How does α-actinin-3 deficiency alter muscle function? Mechanistic insights into ACTN3, the 'gene for speed'. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:686-93. [PMID: 26802899 DOI: 10.1016/j.bbamcr.2016.01.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/15/2016] [Accepted: 01/19/2016] [Indexed: 01/18/2023]
Abstract
An estimated 1.5 billion people worldwide are deficient in the skeletal muscle protein α-actinin-3 due to homozygosity for the common ACTN3 R577X polymorphism. α-Actinin-3 deficiency influences muscle performance in elite athletes and the general population. The sarcomeric α-actinins were originally characterised as scaffold proteins at the muscle Z-line. Through studying the Actn3 knockout mouse and α-actinin-3 deficient humans, significant progress has been made in understanding how ACTN3 genotype alters muscle function, leading to an appreciation of the diverse roles that α-actinins play in muscle. The α-actinins interact with a number of partner proteins, which broadly fall into three biological pathways-structural, metabolic and signalling. Differences in functioning of these pathways have been identified in α-actinin-3 deficient muscle that together contributes to altered muscle performance in mice and humans. Here we discuss new insights that have been made in understanding the molecular mechanisms that underlie the consequences of α-actinin-3 deficiency.
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Affiliation(s)
- Fiona X Z Lee
- The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, NSW 2145, Australia; Discipline of Paediatrics and Child Health, Faculty of Medicine, The University of Sydney, NSW 2006, Australia
| | - Peter J Houweling
- Murdoch Childrens Research Institute, the Royal Children's Hospital, VIC 3052, Australia
| | - Kathryn N North
- The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, NSW 2145, Australia; Murdoch Childrens Research Institute, the Royal Children's Hospital, VIC 3052, Australia
| | - Kate G R Quinlan
- Discipline of Paediatrics and Child Health, Faculty of Medicine, The University of Sydney, NSW 2006, Australia; School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW 2052, Australia.
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Murphy ACH, Young PW. The actinin family of actin cross-linking proteins - a genetic perspective. Cell Biosci 2015; 5:49. [PMID: 26312134 PMCID: PMC4550062 DOI: 10.1186/s13578-015-0029-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/22/2015] [Accepted: 06/23/2015] [Indexed: 01/08/2023] Open
Abstract
Actinins are one of the major actin cross-linking proteins found in virtually all cell types and are the ancestral proteins of a larger family that includes spectrin, dystrophin and utrophin. Invertebrates have a single actinin-encoding ACTN gene, while mammals have four. Mutations in all four human genes have now been linked to heritable diseases or traits. ACTN1 mutations cause macrothrombocytopenia, a platelet disorder characterized by excessive bleeding. ACTN2 mutations have been linked to a range of cardiomyopathies, and ACTN4 mutations cause a kidney condition called focal segmental glomerulosclerosis. Intriguingly, approximately 16 % of people worldwide are homozygous for a nonsense mutation in ACTN3 that abolishes actinin-3 protein expression. This ACTN3 null allele has undergone recent positive selection in specific human populations, which may be linked to improved endurance and adaptation to colder climates. In this review we discuss the human genetics of the ACTN gene family, as well as ACTN gene knockout studies in several model organisms. Observations from both of these areas provide insights into the evolution and cellular functions of actinins.
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Affiliation(s)
- Anita C H Murphy
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Paul W Young
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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Deschamps CL, Connors KE, Klein MS, Johnsen VL, Shearer J, Vogel HJ, Devaney JM, Gordish-Dressman H, Many GM, Barfield W, Hoffman EP, Kraus WE, Hittel DS. The ACTN3 R577X Polymorphism Is Associated with Cardiometabolic Fitness in Healthy Young Adults. PLoS One 2015; 10:e0130644. [PMID: 26107372 PMCID: PMC4480966 DOI: 10.1371/journal.pone.0130644] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/21/2015] [Indexed: 12/03/2022] Open
Abstract
Homozygosity for a premature stop codon (X) in the ACTN3 “sprinter” gene is common in humans despite the fact that it reduces muscle size, strength and power. Because of the close relationship between skeletal muscle function and cardiometabolic health we examined the influence of ACTN3 R577X polymorphism over cardiovascular and metabolic characteristics of young adults (n = 98 males, n = 102 females; 23 ± 4.2 years) from our Assessing Inherent Markers for Metabolic syndrome in the Young (AIMMY) study. Both males and females with the RR vs XX genotype achieved higher mean VO2 peak scores (47.8 ± 1.5 vs 43.2 ±1.8 ml/O2/min, p = 0.002) and exhibited higher resting systolic (115 ± 2 vs 105 ± mmHg, p = 0.027) and diastolic (69 ± 3 vs 59 ± 3 mmHg, p = 0.005) blood pressure suggesting a role for ACTN3 in the maintenance of vascular tone. We subsequently identified the expression of alpha-actinin 3 protein in pulmonary artery smooth muscle, which may explain the genotype-specific differences in cardiovascular adaptation to acute exercise. In addition, we utilized targeted serum metabolomics to distinguish between RR and XX genotypes, suggesting an additional role for the ACTN3 R577X polymorphism in human metabolism. Taken together, these results identify significant cardiometabolic effects associated with possessing one or more functional copies of the ACTN3 gene.
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Affiliation(s)
- Chelsea L. Deschamps
- Faculty of Kinesiology, University of Calgary, 2500 University Drive, Calgary, Alberta, T2N 1N4, Canada
| | - Kimberly E. Connors
- Faculty of Kinesiology, University of Calgary, 2500 University Drive, Calgary, Alberta, T2N 1N4, Canada
| | - Matthias S. Klein
- Faculty of Kinesiology, University of Calgary, 2500 University Drive, Calgary, Alberta, T2N 1N4, Canada
| | - Virginia L. Johnsen
- Faculty of Kinesiology, University of Calgary, 2500 University Drive, Calgary, Alberta, T2N 1N4, Canada
| | - Jane Shearer
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, 2500 University Drive, Calgary, Alberta, T2N 1N4, Canada
- Faculty of Kinesiology, University of Calgary, 2500 University Drive, Calgary, Alberta, T2N 1N4, Canada
| | - Hans J. Vogel
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, 2500 University Drive, Calgary, Alberta, T2N 1N4, Canada
| | - Joseph M. Devaney
- Children’s National Medical Center, 111 Michigan Ave NW, Washington DC, United States of America
| | - Heather Gordish-Dressman
- Children’s National Medical Center, 111 Michigan Ave NW, Washington DC, United States of America
| | - Gina M. Many
- Children’s National Medical Center, 111 Michigan Ave NW, Washington DC, United States of America
| | - Whitney Barfield
- Children’s National Medical Center, 111 Michigan Ave NW, Washington DC, United States of America
| | - Eric P. Hoffman
- Children’s National Medical Center, 111 Michigan Ave NW, Washington DC, United States of America
| | - William E. Kraus
- Duke University, 304 Research Drive, Durham, NC, United States of America
| | - Dustin S. Hittel
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, 2500 University Drive, Calgary, Alberta, T2N 1N4, Canada
- * E-mail:
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Differing evolutionary histories of the ACTN3*R577X polymorphism among the major human geographic groups. PLoS One 2015; 10:e0115449. [PMID: 25706920 PMCID: PMC4338210 DOI: 10.1371/journal.pone.0115449] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 11/24/2014] [Indexed: 01/23/2023] Open
Abstract
It has been proposed that the functional ACTN3*R577X polymorphism might have evolved due to selection in Eurasian human populations. To test this possibility we surveyed all available population-based data for this polymorphism and performed a comprehensive evolutionary analysis of its genetic diversity, in order to assess the action of adaptive and random mechanisms on its variation across human geographical distribution. The derived 577X allele increases in frequency with distance from Africa, reaching the highest frequencies on the American continent. Positive selection, detected by an extended haplotype homozygosisty test, was consistent only with the Eurasian data, but simulations with neutral models could not fully explain the results found in the American continent. It is possible that particularities of Native American population structure could be responsible for the observed allele frequencies, which would have resulted from a complex interaction between selective and random factors.
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Altered Ca2+ kinetics associated with α-actinin-3 deficiency may explain positive selection for ACTN3 null allele in human evolution. PLoS Genet 2015; 11:e1004862. [PMID: 25590636 PMCID: PMC4295894 DOI: 10.1371/journal.pgen.1004862] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/29/2014] [Indexed: 11/28/2022] Open
Abstract
Over 1.5 billion people lack the skeletal muscle fast-twitch fibre protein α-actinin-3 due to homozygosity for a common null polymorphism (R577X) in the ACTN3 gene. α-Actinin-3 deficiency is detrimental to sprint performance in elite athletes and beneficial to endurance activities. In the human genome, it is very difficult to find single-gene loss-of-function variants that bear signatures of positive selection, yet intriguingly, the ACTN3 null variant has undergone strong positive selection during recent evolution, appearing to provide a survival advantage where food resources are scarce and climate is cold. We have previously demonstrated that α-actinin-3 deficiency in the Actn3 KO mouse results in a shift in fast-twitch fibres towards oxidative metabolism, which would be more “energy efficient” in famine, and beneficial to endurance performance. Prolonged exposure to cold can also induce changes in skeletal muscle similar to those observed with endurance training, and changes in Ca2+ handling by the sarcoplasmic reticulum (SR) are a key factor underlying these adaptations. On this basis, we explored the effects of α-actinin-3 deficiency on Ca2+ kinetics in single flexor digitorum brevis muscle fibres from Actn3 KO mice, using the Ca2+-sensitive dye fura-2. Compared to wild-type, fibres of Actn3 KO mice showed: (i) an increased rate of decay of the twitch transient; (ii) a fourfold increase in the rate of SR Ca2+ leak; (iii) a threefold increase in the rate of SR Ca2+ pumping; and (iv) enhanced maintenance of tetanic Ca2+ during fatigue. The SR Ca2+ pump, SERCA1, and the Ca2+-binding proteins, calsequestrin and sarcalumenin, showed markedly increased expression in muscles of KO mice. Together, these changes in Ca2+ handling in the absence of α-actinin-3 are consistent with cold acclimatisation and thermogenesis, and offer an additional explanation for the positive selection of the ACTN3 577X null allele in populations living in cold environments during recent evolution. α-Actinin-3 is a protein found inside the muscles of most people around the world. It is encoded by a gene called ACTN3, popularly known as “the gene for speed.” In 1.5 billion people, a certain variation in the genetic sequence of their ACTN3 gene causes their muscles to produce no α-actinin-3 protein at all. These people have no muscle disease; however, in elite athletes, a lack of α-actinin-3 seems to be beneficial for endurance activities and detrimental to sprinting activities. Intriguingly, α-actinin-3 deficiency varies in frequency across the globe, being most common in European and Asian populations and least common in African populations. During recent human evolution, there appears to have been strong positive selection for α-actinin-3 deficiency in places where food resources are relatively scarce and climate is cold. We have previously demonstrated that α-actinin-3 deficiency in the Actn3 knockout (KO) mouse causes a shift towards more “energy efficient” forms of muscle metabolism which would enhance survival in times of famine, and benefit endurance performance. Our present study, using single muscle fibres from Actn3 KO mice, demonstrates changes in calcium handling that would adapt muscles to cold environments and provide a survival advantage in cold climates.
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Affiliation(s)
- Niklas Ivarsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Håkan Westerblad
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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Zebrick B, Teeramongkolgul T, Nicot R, Horton MJ, Raoul G, Ferri J, Vieira AR, Sciote JJ. ACTN3 R577X genotypes associate with Class II and deepbite malocclusions. Am J Orthod Dentofacial Orthop 2014; 146:603-11. [PMID: 25439211 DOI: 10.1016/j.ajodo.2014.07.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 07/01/2014] [Accepted: 07/01/2014] [Indexed: 01/02/2023]
Abstract
INTRODUCTION α-Actinins are myofibril anchor proteins that influence the contractile properties of skeletal muscles. ACTN2 is expressed in slow type I and fast type II fibers, whereas ACTN3 is expressed only in fast fibers. ACTN3 homozygosity for the 577X stop codon (ie, changing 577RR to 577XX, the R577X polymorphism) results in the absence of α-actinin-3 in about 18% of Europeans, diminishes fast contractile ability, enhances endurance performance, and reduces bone mass or bone mineral density. We have examined ACTN3 expression and genetic variation in the masseter muscle of orthognathic surgery patients to determine the genotype associations with malocclusion. METHODS Clinical information, masseter muscle biopsies, and saliva samples were obtained from 60 subjects. Genotyping for ACTN3 single nucleotide polymorphisms, real-time polymerase chain reaction quantitation of muscle gene message, and muscle morphometric fiber type properties were compared to determine statistical differences between genotype and phenotype. RESULTS Muscle mRNA expression level was significantly different for ACTN3 single nucleotide polymorphism genotypes (P <0.01). The frequency of ACTN3 genotypes was significantly different for the sagittal and vertical classifications of malocclusion, with the clearest association being elevated 577XX genotype in skeletal Class II malocclusion (P = 0.003). This genotype also resulted in significantly smaller diameters of fast type II fibers in masseter muscles (P = 0.002). CONCLUSION ACTN3 577XX is overrepresented in subjects with skeletal Class II malocclusion, suggesting a biologic influence during bone growth. ACTN3 577XX is underrepresented in subjects with deepbite malocclusion, suggesting that muscle differences contribute to variations in vertical facial dimensions.
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Affiliation(s)
- Brian Zebrick
- Resident, Department of Orthodontics, Temple University, Philadelphia, Pa
| | | | - Romain Nicot
- Resident, Oral and Maxillofacial Department, Université Lille Nord de France, Lille, France
| | - Michael J Horton
- Research assistant professor, Department of Orthodontics, Temple University, Philadelphia, Pa
| | - Gwenael Raoul
- Professor, Department of Oral and Maxillofacial, Université Lille Nord de France, Lille, France; UDSL, Roger Salengro Hospital, CHU; and INSERM U 1008, Controlled Drug Delivery Systems and Biomaterials, Lille, France
| | - Joel Ferri
- Professor and head, Department of Oral and Maxillofacial Surgery, Université Lille Nord de France, Lille, France; UDSL, Roger Salengro Hospital, CHU; and INSERM U 1008, Controlled Drug Delivery Systems and Biomaterials, Lille, France
| | - Alexandre R Vieira
- Associate professor, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pa
| | - James J Sciote
- Professor, Department of Orthodontics, Temple University, Philadelphia, Pa.
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Confidence intervals for population allele frequencies: the general case of sampling from a finite diploid population of any size. PLoS One 2014; 9:e85925. [PMID: 24465792 PMCID: PMC3897575 DOI: 10.1371/journal.pone.0085925] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 12/04/2013] [Indexed: 11/19/2022] Open
Abstract
The estimation of population allele frequencies using sample data forms a central component of studies in population genetics. These estimates can be used to test hypotheses on the evolutionary processes governing changes in genetic variation among populations. However, existing studies frequently do not account for sampling uncertainty in these estimates, thus compromising their utility. Incorporation of this uncertainty has been hindered by the lack of a method for constructing confidence intervals containing the population allele frequencies, for the general case of sampling from a finite diploid population of any size. In this study, we address this important knowledge gap by presenting a rigorous mathematical method to construct such confidence intervals. For a range of scenarios, the method is used to demonstrate that for a particular allele, in order to obtain accurate estimates within 0.05 of the population allele frequency with high probability (%), a sample size of is often required. This analysis is augmented by an application of the method to empirical sample allele frequency data for two populations of the checkerspot butterfly (Melitaea cinxia L.), occupying meadows in Finland. For each population, the method is used to derive % confidence intervals for the population frequencies of three alleles. These intervals are then used to construct two joint % confidence regions, one for the set of three frequencies for each population. These regions are then used to derive a % confidence interval for Jost's D, a measure of genetic differentiation between the two populations. Overall, the results demonstrate the practical utility of the method with respect to informing sampling design and accounting for sampling uncertainty in studies of population genetics, important for scientific hypothesis-testing and also for risk-based natural resource management.
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